Regular paracetamol use during pregnancy is linked to changes in the development of the female reproductive system in daughters, scientists reported in the medical journal Human Reproduction Open.
An examination of three-month-old female infants revealed that those exposed to the medication in the womb developed smaller reproductive organs and fewer immature egg cells compared to unexposed infants.
Researchers monitored 685 pregnant women who regularly reported their paracetamol intake and provided test samples. Scientists later examined 302 of the daughters born to the participants at three months of age, comparing 159 girls exposed to the drug during prenatal development against a control group of 143 girls.
Medical evaluations showed that girls whose mothers took paracetamol had an average ovarian volume 40 percent smaller than those in the control group. Their uterine volume was 13 percent smaller, and their count of follicles containing immature egg cells was 23 percent lower.
Hormonal indicators and developmental findings
Exposure to the drug during early pregnancy was also associated with lower levels of anti-Müllerian hormone, an indicator linked to a female's egg reserve. Researchers noted that similar reproductive alterations were also detected in a separate group of girls who were monitored through to adolescence.
Anti-Müllerian hormone is a protein hormone secreted by cells within the ovarian follicles. In clinical medicine, levels of this hormone are measured to evaluate ovarian reserve, providing an estimate of the remaining pool of egg cells in the ovaries.
Ovarian follicles are small, fluid-filled sacs located inside the ovaries that house undeveloped egg cells. In female human biology, the lifetime supply of egg cells is established entirely during fetal development in the womb, meaning early structural changes can influence long-term reproductive organ capacity.
Human Reproduction Open is a peer-reviewed, open-access scientific journal published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology, specializing in reproductive medicine and developmental biology.
Medical advice and study limitations
The study authors stated that it remains unknown whether the observed changes could affect future fertility or the age of menopause onset. They emphasized that the study was observational and does not prove that paracetamol directly caused the reproductive differences.
The authors stressed that pregnant women should not independently stop taking paracetamol if it is medically necessary. They advised that decisions regarding treatment during pregnancy should always be made in consultation with a doctor.
Paracetamol, also known as acetaminophen, is one of the most widely used over-the-counter pain relievers and fever reducers globally. It is commonly recommended as a first-line treatment for pain during pregnancy because alternative medications carry known risks.
Painkiller research context
The findings add to a broader body of research investigating the long-term biological effects of common non-prescription pain medications. Previous research by scientists has shown that regular use of ibuprofen reduces the risk of developing endometrial cancer, a type of cancer that begins in the inner lining of the uterus.
